Search

Lacertid and amphisbaenian lizards are two squamate reptile lineages very divergent morphologically. In fact, adaptation to burrowing deeply modified amphisbaenian worm-like body. Lacertids instead have a typical reptile morphology with a long tail and four well-developed limbs. Despite so different in appearance, they are evolutionarily very close as evidenced by molecular phylogenetic approaches. Consistently, a slow-evolving satellite DNA (IMO-TaqI) described in lacertid lizards was isolated from the genome of the amphisbaenian Trogonophis wiegmanni too. Comparison with lacertid repeats evidenced great similarity, highlighting that molecular characters appeared very suitable especially when morphology is subjected to strong selective pressures. [ABSTRACT FROM AUTHOR]

Lacertid and amphisbaenian lizards are two squamate reptile lineages very divergent morphologically. In fact, adaptation to burrowing deeply modified amphisbaenian worm-like body. Lacertids instead have a typical reptile morphology with a long tail and four well-developed limbs. Despite so different in appearance, they are evolutionarily very close as evidenced by molecular phylogenetic approaches. Consistently, a slow-evolving satellite DNA (IMO-TaqI) described in lacertid lizards was isolated from the genome of the amphisbaenian Trogonophis wiegmanni too. Comparison with lacertid repeats evidenced great similarity, highlighting that molecular characters appeared very suitable especially when morphology is subjected to strong selective pressures.

Simple Summary: Soil alterations may negatively affect the health of animals living inside these soils, but these negative effects are often unexplored and remain "hidden" underground. This study examines the validity of a non-invasive technique to quantify glucocorticoid levels of the amphisbaenian Trogonophis wiegmanni, a fossorial burrowing reptile. Quantification of corticosterone metabolites was made from fresh fecal samples using an enzyme immunoassay kit. An experimental external supplementation of corticosterone to a group of amphisbaenians was detected in their feces as an increase in their fecal glucocorticoid metabolite levels, confirming that this treatment can be used to induce physiological increases of this hormone in these animals. We also quantified baseline fecal glucocorticoid metabolite levels in a field population of this amphisbaenian using this technique. Results showed that although there were no differences between sexes, sizes, or seasons, there was a high interindividual variation, which may allow using this measurement and technique to examine in detail the environmental causes that may produce this variation. To understand wildlife responses to the changing environment, it is useful to examine their physiological responses and particularly their endocrine status. Here, we validated an enzyme immunoassay (EIA) to non-invasively quantify fecal corticosterone metabolites (FCM) in the fossorial amphisbaenian reptile Trogonophis wiegmanni from North Africa. We supplemented animals assigned to the treatment group with corticosterone dissolved in oil applied non-invasively on the skin for several days, while control groups received the oil-alone solution. Fresh feces were collected at the end of the supplementation period, and FCM levels were quantified by an EIA. Basal FCM levels were similar for both treatments and increased at the end of the test, but FCM increased significantly more in corticosterone-treated animals. A further examination of FCM levels in a wild population of this amphisbaenian did not find overall sexual, size or seasonal differences but showed a high range of variation among individuals. This suggests that different uncontrolled intrinsic or local environmental variables might increase the circulating glucocorticoid levels of different individuals. Our results confirmed the suitability of EIA for analyzing physiological changes in FCM in this amphisbaenian species. This technique may be useful for understanding and remediating the little-explored potential stressors of the soil environment that may negatively affect the health state of fossorial reptiles. [ABSTRACT FROM AUTHOR]

DNA sequencing, using traditional Sanger sequencing methods, has revolutionized parasitology research, with advancements in both parasite detection and phylogenetic reconstruction. Currently, high-throughput sequencing (HTS) technologies are available and can be used to screen simultaneously for multiple parasites via a metabarcoding approach, in a cheaper, faster and still accurate manner. However, the effectiveness of this new tool still needs to be further assessed to determine the full extent of both its potential and limitations. We employed this approach to detect the presence of blood parasites in fossorial reptiles. In this way we intended to both validate a recent hypothesis that fossorial reptiles may not be parasitized and to examine the potency of this technique. We indicate the presence of species of Hepatozoon in Trogonophis wiegmanni, thereby refuting the hypothesis that these parasites are not present due to the fossorial lifestyle of the host. We also detected a species of Sarcocystis for the first time in a species of Blanus, further demonstrating the value of the HTS approach. [ABSTRACT FROM AUTHOR]

To understand wildlife responses to the changing environment, it is useful to examine their physiological responses and particularly their endocrine status. Here, we validated an enzyme immunoassay (EIA) to non-invasively quantify fecal corticosterone metabolites (FCM) in the fossorial amphisbaenian reptile Trogonophis wiegmanni from North Africa. We supplemented animals assigned to the treatment group with corticosterone dissolved in oil applied non-invasively on the skin for several days, while control groups received the oil-alone solution. Fresh feces were collected at the end of the supplementation period, and FCM levels were quantified by an EIA. Basal FCM levels were similar for both treatments and increased at the end of the test, but FCM increased significantly more in corticosterone-treated animals. A further examination of FCM levels in a wild population of this amphisbaenian did not find overall sexual, size or seasonal differences but showed a high range of variation among individuals. This suggests that different uncontrolled intrinsic or local environmental variables might increase the circulating glucocorticoid levels of different individuals. Our results confirmed the suitability of EIA for analyzing physiological changes in FCM in this amphisbaenian species. This technique may be useful for understanding and remediating the little-explored potential stressors of the soil environment that may negatively affect the health state of fossorial reptiles.

Morphological adaptations of amphisbaenians for a fossorial life constrain their ecological demands in a greater way than for epigeal reptiles. Studies on the diet of amphisbaenians suggest that most species are generalists, although others seem more selective. However, there is no information on the diet preferences of almost any species because most studies did not evaluate the availability of prey in the environment. We analysed the spring diet selection of a population of the amphisbaenian Trogonophis wiegmanni from the Chafarinas Islands, in North Africa. We specifically examined diet estimated from faecal material collected from live amphisbaenians and compared diet with the availability of invertebrates in the soil. Results indicate that the diet of T. wiegmanni amphisbaenians consists of some of the types of invertebrates that are more commonly found under rocks used by amphisbaenians, such as insect larvae, snails, isopods, beetles and ants. This diet could be initially considered generalist, and probably opportunistic. However, the comparison of proportions of prey types in the diet and those available in the habitat revealed that T. wiegmanni does not eat prey at random, but selects some particular prey types (insect larvae and pupae and, surprisingly, snails), while others (ants and isopods) are consumed less than expected by their abundance. We did not found differences between sexes or age classes in diet composition. We discuss how diet preferences could be due to selection of the more profitable or easily captured prey. There are many aspects of the feeding and foraging biology of amphisbaenians that remain unknown and further studies are clearly needed. [ABSTRACT FROM AUTHOR]

Amphisbaenians are reptiles specialized for a fossorial lifestyle, which may limit their opportunities for microhabitat selection in comparison with epigeal reptiles. We hypothesized that, given the fossorial habits of amphisbaenians, a detailed analysis of the physical and chemical properties of the soil may reveal their patterns of habitat use. We investigated microhabitat and soil use by a population of the amphisbaenian Trogonophis wiegmanni from the Chafarinas Islands ( North- West Africa) and compared them with those available in the habitat. Results showed that some soil physical and chemical characteristics determined microhabitat use by T. wiegmanni. Amphisbaenians selected soils that were relatively sandy, basic, carbonated and shallow, having a high cover of medium-sized rocks, whereas they avoided marine salinized, more acid and deeper heavy-textured soils (i.e. with percentages of silt comparatively high), and those covered mainly by small rocks. No differences were found between soils with and without influence of seabird colonies, although this was the main driver of soil chemical variations in these Islands. Vegetation cover per se did not seem to have a direct influence on microhabitat use. We discuss how energetic costs of burrowing and the direct and indirect influences of soil chemical properties could explain these patterns of habitat use. [ABSTRACT FROM AUTHOR]

Amphisbaenians are a group of reptiles specialized for a fossorial life, which makes the study of their peculiar biological and ecological adaptations difficult. The population biology of amphisbaenians is almost unknown. We described the seasonal variation in the size, age, and sex structure of a population of the amphisbaenian Trogonophis wiegmanni from the Chafarinas Islands, in North Africa. We specifically described body size (length and weight), frequency distribution of newborn and older juvenile individuals and adults, sex ratio of adults (which did not differ from a 1:1 ratio), and proportion of juveniles and newborn individuals in the population. The results indicated that T. wiegmanni is a viviparous species that delays reproduction until at least 2.5 yr, that almost half of adult females do not reproduce every year, and that females have a very small brood size (i.e., reproductive females give birth to a single juvenile at the beginning of autumn). We also used our data to infer growth and survival of juveniles, suggesting that mortality of newborn individuals is low. There are many aspects of the population biology of amphisbaenians that remain unknown and further studies are clearly needed. [ABSTRACT FROM AUTHOR]